Speed cameras on just one stretch of road in Brighton trapped more than 12,000 drivers and raised £750,000 in fines, it was revealed today.

It was by far the biggest revenue-earning area for cameras in Sussex and accounted for a fifth of all fines in the county.

The money came in through temporary cameras placed on both sides of the A27 Brighton-Lewes highway while workmen dug a subway for Sussex University students and staff at Falmer.

The Falmer fines, £60-a-time, almost matched the cost of the subway project - £1 million.

The road is one of the busiest in Sussex but even experts are at a loss as to why so many drivers failed to slow from 70mph to beat the 40mph-limit camera traps.

A spokeswoman for the Sussex Safety Camera Partnership (SSCP) said: "It is well travelled by commuters and we can only speculate that many switched off' while driving, which is scary."

The subway work began in October 2002 and was completed in March 2003. Revenue from fines during that period was received during 2003/04 and the results from that year were published today.

Fine revenue for all speed and traffic light cameras for the year amounted to £3,772,800, all of which went to the Government's Department for Constitutional Affairs.

The DCA handed back the majority for more Sussex safety-camera schemes, maintenance, camera running costs, road safety education, publicity and projects.

But it kept £1.5 million, adding to the suspicion held by critics that cameras are just money-making machines for the Government.

On a positive note, the SSCP's annual report showed serious injury crashes and deaths were cut by 31 per cent at fixed camera sites and 16 per cent at sites where mobile cameras were used.

The percentage of drivers travelling above the limit before cameras were installed was 52 and that has dropped to 27, four per cent less than the previous year.